Bump postcss from 8.4.29 to 8.4.31 in /web (#3336)

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.29 to 8.4.31.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.4.29...8.4.31)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: direct:development
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

web/package.json

@@ -113,7 +113,7 @@
 		"mdx-mermaid": "^2.0.0",
 		"mermaid": "^10.0.0",
 		"npm": "^9.4.0",
-		"postcss": "^8.4.24",
+		"postcss": "^8.4.31",
 		"prettier": "3.0.3",
 		"sass": "1.67.0",
 		"sass-loader": "13.3.2",